Tag Archives: hemlock woolly adelgid

Keep An Eye Out For HWA

The winter is a great time to visit State Parks in New York. Even in these colder months, opportunities for recreation are abundant and each year State Parks welcomes cross-country skiers, snowshoers, and hikers, who enthusiastically explore the many miles of trail that are open and maintained for winter activities.

Many recreationists are as eager to hit the trails in the winter as in the warmer months, but most are likely not aware that by enjoying their favorite winter past-time, they are also able to aid State Parks Biologists and staff in detecting an insidious invasive pest.

The Hemlock Woolly Adelgid (HWA), is a non-native, invasive aphid-like insect that infests Eastern Hemlocks throughout New York State, and across most of the eastern US. The insect attacks the tree by attaching to the underside of the branch at the base of the needles, and feeding on the sap. The tree will respond by shutting down resources to the damaged areas. Eventually, as the infestation spreads, the tree dies – the insects having essentially sucked the life out of it.

Currently, work is being done throughout NY State to try to slow the spread of this pest. However, in order to combat HWA, researchers first need to know where it has (and hasn’t) been found. This creates an opportunity for concerned and conservation-minded citizens to provide a great service to the parks they love, and to help to protect the natural beauty that they cherish.

Hemlocks, one of many coniferous (cone-bearing) species throughout New York State, can best be identified by their needles, which are flat, generally a little more than an inch long, and have two white lines running parallel on the underside. The winter months are the best time of year to check these trees for HWA. The insects, which lay eggs in the fall, coat the egg sacks with a white, woolly protective layer, which allows the developing young to survive the winter. This white “wool” also makes the egg sacks very visible throughout the winter months (mainly December-March), and allows observers, with little to no formal training, to detect the presence of HWA in hemlocks.

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HWA egg sacks on an Eastern Hemlock branch. Note the two white lines on the underside of the needles. Photo by Alyssa Reid, NYS Parks.

Checking for HWA is easy – simply flip a hemlock branch over, and scan the base of the needles for the presence of white, woolly, round egg-sacks. While some larger hemlocks have branches that are un-reachable, many of the smaller trees have overhanging branches that can easily be reached without leaving the trail. Take note of where you are, and anything that looks suspicious (many smart phones will even allow you to save your location), and let Parks staff know where you found HWA before you head home for the day.

So, as you head out on the trail this season, consider pausing from time-to-time to inspect a nearby hemlock branch or two. NY State’s hemlocks need our help, and you can play an important role in conservation, while enjoying the outdoors!

For more information, or to find out how to volunteer and learn more about HWA and invasive forest pests, contacts NYS Parks Invasive Species Staff: 845-256-0579.

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HWA surveys are an important way to help out, while exploring New York’s winter wonderland. Photo by Alyssa Reid, State Parks

Post by Sarah Travalio, State Parks

Forest Health Specialists: Climbing in Pursuit of Invasive Insects

Forest Health Specialists are an important part of New York State Park’s Invasive Species Management Team. Their work helps protect native plants, wildlife  and forests that are currently being threatened by two non-native invasive species: Hemlock Woolly Adelgid (HWA) and Emerald Ash Borer (EAB). Although these insects are very different from each other in appearance and behavior, they both cause significant destruction and mortality to their host trees.

What do Forest Health Specialists Actually Do?

The Forest Health Specialists are seasonal employees that travel throughout New York State conducting invasive species surveys and monitoring infestations in various Parks. They have training in field biology, forestry, and tree climbing. The team of two camps at the park of interest while completing their work. Surveys involve lots of hiking and investigating trees that look to be in poor health, taking photos, and recording information on location and observations made at each site.

Although hiking in the woods isn’t a bad way to spend a work day, monitoring infestations of HWA is where the job really gets interesting. Specialists need to collect canopy samples from hemlock trees in order to see if insect numbers are declining or increasing. So, using a giant 8-foot slingshot, a line is shot high into the tree to a branch anywhere between 50 to 90 feet above the ground. Then a climbing rope is attached and pulled into the canopy and the fun begins! The Specialist, equipped with a harness and two ascenders (the name for special clips), climbs the rope upwards into the treetop. Climbing can be highly physical but is always rewarding.

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A Forest Health Specialist working their way up to the canopy using a climbing harness that is attached to the rope. Climbs typically take about an hour.
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A bird’s eye view looking down from the top of a hemlock. The tiny speck at in the bottom (in the green shirt and white cap) is the other team member!

So What’s the Goal?

The goal of this program is to get a better grasp of where these invasive species are spreading, assessing their impact on the forests, and ultimately taking action to slow their spread and keep their numbers under control. It also allows biologists and managers to anticipate other impacts to wildlife or rare species; to plan for potential avoidance or removal of hazard trees along trails; and to help others understand changes they see in the forest and landscape around us.

Of course a key component to the program’s success is you! By offering educational programs and volunteer opportunities, Forest Health Specialists also help people all over the state learn about invasive insects. The more people participating in and understanding invasive species in New York; the better chance we have of making a difference in our parks and our communities.

Remember, the best way to stop the spread of Emerald Ash Borer and Hemlock Woolly Adelgid is to avoid introducing them in the first place. Don’t move firewood, take caution in moving landscaping debris around, and clean equipment and vehicles if moving from a site with these pests to somewhere else!

For more information go to NYS DEC website:  www.dec.ny.gov/animals/265.html

Post by Kelly Blood (OPRHP). Photos by Kelly Blood and Alyssa Reid (OPRHP).

 

Invasive Species Spotlight: Monitoring for Hemlock Woolly Adelgid

Hemlock Woolly Adelgid appears as white fluffy balls on the underside of hemlock branches during the cooler months.
Hemlock Woolly Adelgid appears as white fluffy balls on the underside of hemlock branches during the cooler months.

Hemlock Woolly Adelgid (HWA) is a tiny, invasive insect which kills hemlock trees in a matter of 6 years. Please see the previous post on HWA for more information. The insect was introduced in Virginia in the early 1900’s, and has steadily spread since then. New York state contains all stages of HWA infestation. There are heavily infested areas like the lower Hudson Valley, which have harbored HWA for 20+ years and contain increasing numbers of declining and dead hemlocks. Moderately infested areas include the Finger Lakes, where some areas have HWA and some do not. Several HWA early detections were made in Western NY’s Allegany State Park by dedicated volunteers, trained by Park staff to survey for the insect. Allegany just has a few isolated patches of HWA, and State Parks is working to keep those patches small. So far, the Adirondacks have escaped infestation, but they are not immune.

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This map shows the spread of HWA by township since 1987. Map from http://www.dec.ny.gov/animals/7250.html.

How do we know all this information? The first step in determining if HWA is present is simply to look for it. Surveying for HWA takes diligence; the insects’ most visible life stage is the egg sac, which is present in the fall and winter. A hand lens is necessary to identify the tiny adults in the summer. Primarily through grant funding and volunteers, Parks has surveyed for HWA in 20 State Parks, and that number increases every year.

Survey technique demonstration for volunteers in Allegany State Park.
Survey technique demonstration for volunteers in Allegany State Park.

After surveying, maps are created and examined and hemlock stands are prioritized for treatment. Prioritization is a rigorous process which includes collaboration with state and local experts. These experts ask questions like: Do dead/dying hemlocks pose a health and safety risk here? Is there an area of ecological significance, for example, an old growth stand or is there an insect or animal present which is dependent on hemlocks? Will the loss of hemlocks create a significant, negative change to aesthetics? Is this an area of early detection, where treatments could make a big difference?

Mark Whitmore, of Cornell University, gazing at a hemlock in serious decline at Minnewaska State Park Preserve.
Mark Whitmore, of Cornell University, gazing at a hemlock in serious decline at Minnewaska State Park Preserve.

Treatment for HWA does exist. Parks has chosen our methods through regular consultation with experts, based not only on what works, but what has the least impact on the environment. Pesticides are carefully sprayed onto the bark of hemlock trees, in the spring or early fall. The pesticides are taken up rapidly through the bark and into the tree, where hemlock’s circulation system takes it throughout the tree, to all the little branches. The HWA will not survive on treated hemlocks for the next 7 years. While this is certainly not a permanent solution, it does buy us much needed time.

In conjunction with these treatments, Parks is also releasing biological control beetles. Biological control insects have an extensive approval process which can take a decade or more through the USDA. Many states have biological control review processes as well, including NY. These processes are designed to assess and evaluate the insect and its host specificity, the reproductive and cross breeding potential, and other factors. If, and only if, the insect is passes the host specificity and other tests, is it approved for release. Many biological control insects have been explored for control of HWA, one showing some promise is Laricobius nigrinus. These biological control beetles feed exclusively on HWA, and while they will not eliminate their food source, they can keep HWA populations in check so they are no longer killing hemlocks. While this is the ideal end result, it can take a decade or more before this is attained. Releasing a few hundred L. nirginus against millions of HWA means we need to buy time, through the use of pesticides, as these beetles work to increase their populations to levels where they can match HWA and keep it in balance.

Invasive insects are notoriously difficult to contain. While we may never stop the onward march of HWA, we can reduce the negative impacts of hemlock loss in specific areas through human intervention.

Sign up for an upcoming iMap Invasives training to learn how to report HWA when you spot it in State Parks’ forests.

Post and photos by Alyssa Reid.